1. Field of the Invention
Embodiments of the present invention generally relate to a plasma cleaning apparatus and method.
2. Description of the Related Art
Physical vapor deposition (PVD) is a method of depositing a material onto a substrate. A PVD apparatus may have a sputtering target disposed within a processing chamber and situated opposite a substrate. A sputtering gas, such as argon, is introduced into the chamber. The sputtering target, when metallic, may be electrically biased with a DC current to ignite the argon gas into a plasma. The substrate, on the other hand, may be grounded to act as an anode relative to the electrically biased sputtering target. Atoms from the sputtering target may eject or sputter from the sputtering target and deposit on the substrate.
While the atoms from the sputtering target may deposit onto the substrate, the atoms may also deposit on exposed surfaces within the chamber. For example, material may be deposited on the chamber walls. Over time, the material deposited onto the chamber walls may build up to a sufficient thickness that the chamber needs to be cleaned. Additionally, material deposited onto the walls may flake off and land on other areas of the chamber.
When a substrate is inserted or removed from the chamber, opening and closing of a slit valve may cause material to flake off and deposit on undesired surfaces such as the susceptor. When material accumulates onto the susceptor, the susceptor may not function effectively. Thus, the processing chamber may periodically need to be cleaned to remove undesired material deposits.
Additionally, dielectric material may be deposited onto the substrate in other chambers. Whenever the chamber is opened to permit a substrate to enter and/or exit the chamber, dielectric material may enter into the chamber. The dielectric material may be present in the other chamber and flow into the chamber where it may condense on the chamber surfaces, including the susceptor. If the susceptor is an electrostatic chuck and sufficient dielectric material builds up on the susceptor, the electrostatic charge of the susceptor, when biased, may be shielded by the dielectric material and prevent the substrate from being attracted to the susceptor. If there is sufficient dielectric material built up on the susceptor, the substrate may pop off of the susceptor due to insufficient electrostatic charge, possibly resulting in damage to the substrate and/or chamber components.
Therefore, there is a need in the art for an apparatus and a method to clean a processing chamber.